Creep test
The test involves the application of a uniaxial tensile load on a specimen for an extended period, which can extend to several thousand hours. Depending on the configuration, the test can be conducted with constant load or imposed strain.
These tests are critical for preventing structural failure and ensuring the reliability of materials in high-temperature environments, contributing to the safe design of components subject to prolonged stress, such as turbines, heat exchangers, and engine parts.
All Creep tests
Creep tests can be divided into 3 macro-groups
- Stress rupture tests: the test consists of applying a static load to the specimen for a specified duration (interrupted test) or until rupture (uninterrupted test).
- Creep tests: a static load is applied to the specimen for a specified duration (interrupted test) or until failure (uninterrupted test), using an extensometer.
- Relaxation tests: the test consists of applying a constant strain to the specimen for a specific duration (using an extensometer).
Different types of creep tests can be used in different contexts depending on the customer’s needs with respect to material characterization.
How are creep tests performed?
Creep test: procedure and standards
At TEC Eurolab, each creep test is performed according to strict procedures to ensure reliable and repeatable results. The test standards for creep testing involve the application of a controlled uniaxial load on a specimen, maintained at a constant temperature for an extended period, in order to monitor the deformation of the material over time.
The standards and test regulations for performing creep testing are as follows:
- EVS-EN ISO 204 and ASTM E139 – creep and stress rupture tests on metallic materials
- ASTM E292 – Time-to-rupture on notched specimen – metallic materials
- UNI EN 10319-1 and ASTM E328 – Tensile relaxation test – metallic materials.
Methods of analysis of Creep Tests
Analysis of the data obtained from a creep test is critical to understanding the long-term behavior of a material and predicting its durability under critical operating conditions. During a creep test, data on deformation over time are recorded and analyzed through mathematical models that describe the different phases of the phenomenon: the initial transient deformation phase, the secondary phase at constant velocity, and the tertiary phase that precedes failure.
Different results can be determined for each type of creep test:
- Stress rupture (time-to-rupture) tests: test time, elongation after test, and striation after test
- Creep tests: the whole test curve and measurement of creep modulus
- relaxation tests: relaxation curve (decrease in load response over time)
This data directly influences material selection, allowing alloys with better mechanical performance to be chosen depending on the required operating conditions. With in-depth analysis, companies can optimize component design, reduce failure risks, and improve the safety and durability of structures exposed to prolonged stress.
Determine the performance of the material subjected to a constant load
Creep tests with TEC Eurolab
In TEC Eurolab’s mechanical testing department, we carry out the full range of hot static mechanical tests, particularly creep and stress rupture tests.
The segments usually interested in this kind of testing are those where the performance of the material is the most demanding and there is a need to know the material under operating conditions.
At the level of sectors, the most interested are Aerospace, Energy, Oil&Gas, with particular interest from parts of forgers, tube mills and foundries for castings in special alloys in addition to the now cross-cutting additive manufacturing.
At TEC Eurolab you can find qualified personnel with technical expertise and specific know-how. Our integrated approach allows us to respond with completeness and professionalism to the customer’s needs, ensuring clear test results and adequate technical support for the characterization of your material.
We can perform a wide range of creep tests on different specimen geometries and at different temperatures. Our equipment allows us to perform tensile tests on both cylindrical and prismatic specimens of different sizes and different thicknesses according to ASTM or EN ISO standards. On these types of tests, the full scale of the available machines is 50kN and the maximum test temperature 1040°C.